State REMOVES Cyanobacteria Lake Warning for Hunkins Pond in Sanbornton, New Hampshire

Concord, NH –The New Hampshire Department of Environmental Services (NHDES) has REMOVED a cyanobacteria lake warning issued on 9/7/2018 for Hunkins Pond. Nearshore green-scums were mostly large masses of green, filamentous algae (non-cyanobacteria). However, the water also appeared green, turbid and slightly cloudy throughout the water column. Samples were collected away from these nearshore scums and an abundance of cyanobacteria were found. The state threshold for a warning or advisory is 70,000 cells/ml of cyanobacteria in NH lake water. On September 7, 2018 samples contained 87,500 cells per milliliter of cyanobacteria with varieties of Anabaena/Dolichospermum and Woronichinia. On September 14, single filaments of Aphanizomenon (non-rafted) were observed, in addition to Anabaena/Dolichospermum and Woronichinia, with a total cell count of roughly 100,000 cells/ml. By September 25, the cyanobacteria count had peaked at 268,400 cells/ml and Aphanizomenon appeared rafted or in colonies. The following week, on October 5, there were 159,000 cells/ml of Aphanizomenon, Anabaena/Dolichospermum and Woronichinia. On October 12, the same varieties of cyanobacteria were still observed, with an addition of very few colonies of Microcystis. The cell count total was 115,000 cells/ml. On October 19, the same cyanobacteria types were again observed, with concentrations of 91,500 cells/ml. On October 26, there was only one filament of Anabaena/Dolichospermum observed, with about 50 cells/ml. Please continue to monitor your individual shoreline for changing conditions.

Cyanobacteria are natural components of water bodies worldwide, but blooms and surface scums may form when excess nutrients are available to the water. Some cyanobacteria produce toxins that are stored within the cells that can be released upon cell death. Toxins can cause both acute and chronic health effects that range in severity. Acute health effects include irritation of skin and mucous membranes, tingling, numbness, nausea, vomiting, seizures and diarrhea. Chronic effects include liver and central nervous system damage.

NHDES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions typically where lake water has a surface scum, green streaks or blue-green flecks aggregating along the shore. NHDES also advises pet owners to keep their pets out of any waters that have a cyanobacteria bloom.

NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria lake warning or beach advisory has been issued, NHDES returns to affected waterbodies on a weekly basis until the cyanobacteria standards are again met.

The warning went into effect on September 7, 2018 and was removed on October 26, 2018.

If you notice anything resembling cyanobacteria, please refrain from wading, swimming, or drinking the water. Keep all pets out of the water and contact NHDES immediately. Please call NHDES to report a cyanobacteria bloom at (603) 848-8094.